Either the world is coming to an end or the main (good guy) character is about to eat it from something really large (like the common low-speed nuclear blast) and they know there's nothing they can do.
Then it all fades to white, all nice, neat and tidy.
Just once I'd love to see them tossed through the air in a flying sea of debris, screaming as they're blasted into pieces and burned to a crisp, just to freak out the audience.
Or, how about when the world is ending, and the power is still on up to the very last millisecond? The power here sometimes goes out if it's just more than a little breezy!